Upgrading Raspbian 9 to Raspbian 10

In Chapter 15, PyQt Raspberry Pi, Raspbian 10 is required so that you can have a sufficiently recent version of Python and PyQt5. At the time of publication, the current release of Raspbian is version 9, with version 10 expected in mid-to-late 2019. You can, however, upgrade to the testing version of Raspbian 10, which will work correctly for the purposes of this book.

To do so, follow these steps:

1. First, verify that you're using Raspbian 9 by checking the contents of /etc/issue. It should read as follows:

  $ Rasbpian GNU/Linux 9 \n \l

2. Open Command Prompt and, using sudo, edit /etc/apt/sources.list:

  $ sudo -e /etc/apt/sources.list

3. Change every instance of stretch to buster. For example, the first line should read as follows:

deb http://raspbian.raspbrrypi.org/raspbian/
 buster main contrib non-free rpi

4. Run the sudo apt update command...